Method of bending skelp



J W FREE METHOD OF BENDING SKELP. APPLICAHON FILED Aueu, I920. 1,374,146, Patented Apr. 5, 1921.

* SHEETS :HEETI 61/ OVA/Wm,

J. W. FREE.

METHOD OF BENDING SKELP.

APPLICATION HLED AUG-24, 1920.

Patented Apr. 5, 1921.

3 SHEETS-SHEET 2.

H! Q Will" H II j E11 15" q; Q;

/N VEN 70/? WITNESSES v w. aw

L 6 m6 QM WZW, Mi

SKEL

' AUG.24, 1920. 1,374,146. tented Apr. 5, 1921.

3 SHEETS-SHEET a.

UNITED STATES PATENT OFFICE.

JOHN W. FREE-,0]? WOODLAWN, PENNSYLVANIA, ASSIGNOR TO JONES & LAUGrI-ILIN STEEL COMPANY, OF PITTSBURGH, SYLVANIA.

PENNSYLVANIA, A CORPORATION OF PENN- ME'I'HOD OF BENDING SKELP.

Patented Apr. 5, 1921;

Application filed August 24, 1920. Serial No. 405,758. i

T 0 aZZ whom it may concern Be it known that I, JOHN /V FREE, residing at VVoodlawn, in the county of Beaver and State of Pennsylvania, a citizen of the United States, have invented or discovered "certain new and useful Improvements. in

Methods of Bending Skelp, of whichimprovements the following is a specification.

My invention relates to improvements in method for bending pipe skelp preparatory to welding, and more particularly to the bending of skelp for lap-welding and bringing it to tubular form with overlapped edges while in unheated condition.

In a companion application Serial No. 365,009, filed March 11th, 1920, I have described and claimed a mill in the operation of which the method is performed. In this application I shall describe and claim the method as distinct from instrumentalities by which the operation is performed. However, since the method is performed in the operation of the mill alluded to, I shall now describe that mill and its operation.

In the accompanying drawings Figure I is a view of the mill in side elevation; Fig. II is a view of it in plan; Fig. III is a vertical transverse section, on the plane indicatedby the line IIL-III, Fig. I; Fig. IV is a view in elevation of one of the pairs of rolls detached; and Fig. V is a fragmentary view to larger scale, showing in elevation one of the guides for the-material in its advance from one roll pass to another. Figs. VI to XII inclusive show in vertical section the successive roll passes through which the material in the "course of its fabrication passes, and associated with the rolls themselves the material is shown. Above the successive roll passes of the mill as shown in Figs. I and II, I have placed the numerals VI, VII, VIII, etc, thus indicating to which roll pass eachsectional view belongs.

The'mill consists essentially of a succes sion of pairs of-rolls, to mingthesuccession of roll passes illustrated in Figs. VI to XII, inclusive. In Fig. 11,1 have applied the numerals 1 to 7 to "the -upper rolls there shown of thissuccession of pairs.

These rolls, it will be observed, are arranged all of them in parallelpOsitions-in this instance they are all horizontal, and this arrangement makes possible the mount. ing of them all in a common frame or housing 8 and the driving of them, or at least so many of them as are power driven, through the gear train 9 of simple arrangement, suiliciently indicated in Figs. I, II, and III. The intervals at which the successive roll pairs are set are conveniently short, and the mill accordingly'becomes a continuous mill (there 'is no appreciable elongation of the material under treatment). Ordinarily, a single length of material under treatment will in the course of treatmentbe engaged by all or substantially all of the shaping rolls simultaneously.

Between successive roll pairs are arranged suitable guiding means, including the idle beveled rollers 10 mounted on vertical stub shafts and placed in pairs between the passes. One of these guide rollers is illus positions are in as a unit, both vertically and horizontally.

Coming now to the skelp-shaping instrumentalitles and their operation, the develop ment of a skelp into a pipe blank. will be su ficiently understood on careful consid'er- I ation of Figs. VI to XII, with reference to the other figures to make plain the roll-drivmg means.

First of all, a is a be observed that we skelp is developed by transverse bending into a tubular blank'with overlappededgesr a blank of proper "shape and size, and with edges 'suiiiciently overlapped, to und'ergojthe welding operation and producealap-weld pipe of the intended dimensions. The bending of. the blank is developed by beginning radius of the side portions of the now curved blank is diminished to a smaller dimenslon than the mlddle portion. At the same time, however, the middle portion also is preferably reducedsomewhat in. curva ture. In the third pass the curvature of the mid portion is reduced and the whole brought to uniform curvature, preferably to the curvature of the side portions in the second aass' in the fourth iass the radius of the bottom of the now trough-shaped blank, the middle portion of the blank, is still furtherreduced. The lower roll of the fourth pass is the last one to engage the inner surface of the developing blank; both rolls of the fifth pass engage the exterior surface, for the curvature of the blank has now, as Willbe' seen in Fig. 1X, developed until the angular sweep of the are which the blank forms, exceeds 180. In the fifth pass the radius is reduced throughout and made substantially uniform, the two edges of the blank coming now into close proximity, so that the blank now assumes a tubular form. The lower roll of the sixth pass is stepped, and in the sixth pass one edge of theblank is bent inward a distance as great as th thickness of the materiah'and this portion isthus reduced in radius of curvature and brought to substantially its ultimate curvature; otherwise, there is no reduction of curvature in the sixth pass. The seventh pass reduces the radius of curvature of the remainder, constricts the tubular blank to its ultimate dimensions. and brings the edges; to the desired overlapped position;

1 All the roll pairs are preferably positively driven, excepting only the sixth, the pair which effects the depression of one edge relatively to the other. I find it preferable to avoid a frictional tension of roll upon blank here; but instead mount the rolls of this pair for idle turning.

I desire to call attention to the fact that all of the instrumentalities which act upon the material while in the course of forma 'tion to tubular shape ready for lap welding act upon it externally; there is no internal ball nor mandrel upon which the develop known before in the'preparation of blanks for lap weldin V I desire further to note that the shaping instrumentalities engage and exert shaping stress upon and only upon the faces of the skelp, leaving the scarfed edges free of stress, free of shaping contact with roll surfaces or with one another, and so unmutilated and undamaged for the ultimate welding operation. i

l have now described a mill which, in its operation, performs the method of my present invention. The characteristic features of that method. are pointed out in detail in the ensuing claims, and I wish to make plain the fact that the mill has been described in an exemplary way as proper means for performing the method. Heretofore to the best of my knowledge and belief the bending of the skelp ,for lap-welding has involved, and has been supposed to require an initial heating of the material. and heretofore in the bending of skelp for lap welding, it has been the universal practice to bend the skelp over a mandrel, and to the best of my knowledge and belief the use of a mandrel has been deemed to be essential to successful op ration. In the practice of my invention I have, as is now ap Jarent made ain of manifest ractical.

value in those respects.

l cla1m as my invention: 1. The method herein described of de veloping an unheated length of skelp into.

a tubular blank with overlapped edges, which consists in, first, bending the skelp transversely into a tubular blank of uniform radius, second, by externally exerted pressure resisted only by the rigidity of the material, reducing the radius of curvature of one margin of the blank to a greater degree than the remainder, and finally, by externally exerted pressure resisted only by the rigidity of the materiahreducing the radius of curvature of the remainder of the blank.

2. The method herein described of devel oping an unheated length of skelp into a. tubular blank with overlapped edges, which consists, first, in bending the skelp transversely into an arc-shaped blank of uniform curvature, second, developing the curvature of the marginal portions of the blank to curves of less radius than the medial portion, third, reducing the radius of curvature of the medial portion and bringing the whole to uniform curvature, fourth, reducing the radius of curvatureof the medial] portion while that of the marginal portions re-. mains unchanged, fifth, by compressions erted upon the external surface of the article and resisted only by the rigidity of the material itself, reducing the radius of curvature of the marginal portions and bringing the whole to uniformity again, sixth, by

externally exerted pressure resisted only by In testimony whereof I have hereunto set the rigidity of the material, reducing the ramy hand. dius of curvature of one margin to a greater degree than the remainder'of the article, 1 JOHN WV. FREE. and seventh by externally exerted pressure resisted only by the rigidity of the material, Witnesses:

reducing the radius of curvature of the re- G; WILFRED THOMAS,

mainder of the article. L. EARL EVANS. 

